それは何かの間違いだったんですよ。
Sentence Analyzer
English Translation
        That may easily have been a mistake.
    
Furigana
        それは何 かの間違 いだったんですよ。
    
Romanji
        Sore wa nani ka no machigai datta n desu yo.
    
Words
            
                其れ
            
            
                (それ)
            
        
        
            that (indicating an item or person near the listener, the action of the listener, or something on their mind); it; that time; then; there (indicating a place near the listener); you
        
    
            
                は
            
            
                (は)
            
        
        
            topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis
        
    
            
                何
            
            
                (なに、なん)
            
        
        
            what; how many; you-know-what; that; whatsit; what's the expression; what do you call them; what?; hey!
        
    
            
                か
            
            
                (か)
            
        
        
            indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way
        
    
            
                の
            
            
                (の)
            
        
        
            indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question
        
    
            
                間違い
            
            
                (まちがい)
            
        
        
            mistake; error; blunder; accident; mishap; trouble; improper conduct (e.g. between man and woman); indiscretion
        
    
            
                だ
            
            
                (だ)
            
        
        
            be; is; indicates past or completed action; indicates light imperative
        
    
            
                ん
            
            
                (ん)
            
        
        
            yes; yeah; uh huh; negative verb ending used in informal speech (abbr. of negative verb ending "nu"); abbr. of particle "no"; abbr. of particle "ni" (used especially when it precedes the verb "naru")
        
    
            
                です
            
            
                (です)
            
        
        
            be; is
        
    
            
                よ
            
            
                (よ)
            
        
        
            indicates certainty, emphasis, contempt, request, etc.; used when calling out to someone; used to catch one's breath or get someone's attention; yo!